Have you noticed how, in some summers, flaxes and cabbage trees are covered in a mass of flowers? Botanist Dave Kelly set out to find what triggers such mass flowering events in our native snow tussocks, and twenty years later he's still making discoveries. Alison Ballance tracks him down in a tussock-filled greenhouse on the University of Canterbury campus, to find out about a fantastic evolutionary battle of wits between snow tussocks and some tiny seed-eating insects.